A recent U.S. study has found that older people who engage in simple aerobic exercise like walking have improved function in areas of the brain responsible for memory and attention -- in part because of an expansion in brain tissue volume.
"We see increases in volume in different brain regions, and these are in 70-year-old brains," said Art Kramer, a psychologist and neuroscientist at the University of Illinois, who presented his findings Monday to a conference on aging and attention in Toronto.
"And 10 years ago, I don't think people would have expected this. It was all downhill, not uphill."
Exercise to keep mentally fit
In the 2004 study, Kramer and a large research team enrolled 60 healthy but unfit adults aged 60 to 80 for a six-month exercise program. Half began walking for 15 minutes, three times a week, and gradually increased their time to 60 minutes. The other group did toning and stretching exercises for six months.
The researchers then used magnetic resonance imaging to look at brain structure and function in both groups.
"We found that the group that got the aerobic training -- the walking further and faster -- improved the efficiency of neural networks that support attentional and memory processes," Kramer said. "That was due in part to increased brain volume ... both in terms of grey matter and white matter."
Grey matter consists of brain cells, or neurons, while white matter is made up of nerve fibres.
Kramer said the study could not determine whether the increased brain volume means that participants grew new brain cells -- although animal studies have shown that exercise can lead to neuron growth -- but he suggested there may have been at least a boost in synapses, or connections between nerve cells, and in blood vessels supplying oxygen to the brain.
The exercise group also had better short-term memory and an improved ability to focus on important information while excluding confusing or irrelevant stimuli around them, compared to the non-aerobic group, he said.
Socialize and stay sharp
Another program in which Kramer was involved, with researchers at Johns Hopkins University in Baltimore, recruited seniors with low socio-economic status and poor education, "who weren't very engaged in life," to train as teaching assistants for primary school students.
Called the Exercise Corps, the volunteers in their 60s and 70s trained for two months to help kids with literacy and arithmetic as well as helping out in the library. They worked in Baltimore's inner-city schools for a minimum of 15 hours a week for six months.
"These were people who often stayed at home and didn't do much, watched the television," Kramer said. By the end of the study, the participants were showing changes in brain function, underscoring previous studies which show that having friends and social interaction leads to more successful aging and less decrease in memory and attention.
"This is a group that has a high transition rate to dementia because there's so little stimulation in their lives. And all of a sudden, their lives are transformed by this quasi-volunteer opportunity."
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